I’m thinking it’s gold because lead isn’t with cooper meaning that if u switch lead with cooper it won’t work at all .
<u>Answer: </u>The correct statement is X is the effective nuclear charge, and it increases across a period.
<u>Explanation:</u>
We are given that:
X = number of protons − number of core electrons
Effective nuclear charge is defined as the actual nuclear charge (Z = number of protons) minus the screening effect caused by the electrons present between nucleus and valence electrons. These electrons are the core electrons.
The formula used for the calculation of effective nuclear charge given by Slater is:

where,
= effective nuclear charge
Z = atomic number or actual nuclear charge or number of protons
= Screening constant
The effective nuclear charge increases as we go from left to right in a period because nuclear charge increases with no effective increase in screening constant.
Hence, the correct answer is X is the effective nuclear charge, and it increases across a period.
Answer:
C and D
Explanation:
Claims based on science are claims that can be backed up by data and evidence. In the sentence "Data from ice cores show that global temperatures are rising dramatically.", the part "Data from" inclines that there is factually proof backing up the claim. Part of the sentence "Satellite imagery shows.." inclines that there is also proof/evidence backing this claim. The other two sentences are <em>opinions</em> based on science. Instead, they should give some sort of data/evidence that would support that claim.